<template>
    <div class="app-container">

        <h2 style="text-align: center;">发布新课程</h2>

        <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
            <el-step title="填写课程基本信息" />
            <el-step title="创建课程大纲" />
            <el-step title="提交审核" />
        </el-steps>

        <el-form label-width="120px">
            <el-form-item label="课程标题">
                <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写" />
            </el-form-item>
            <el-form-item label="课程类别">
                <el-select v-model="courseInfo.subjectParentId" placeholder="一级分类" @change="subjectLevelOneChanged">
                    <el-option v-for="subject in subjectList" :key="subject.id" :label="subject.title"
                        :value="subject.id" />
                </el-select>
                <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
                    <el-option v-for="subject in subSubjectList" :key="subject.value" :label="subject.title"
                        :value="subject.id" />
                </el-select>
            </el-form-item>
            <el-form-item label="课程讲师">
                <el-select v-model="courseInfo.teacherId" placeholder="请选择">
                    <el-option v-for="teacher in teacherList" :key="teacher.id" :label="teacher.name"
                        :value="teacher.id" />
                </el-select>


            </el-form-item>
            <el-form-item label="总课时">
                <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right"
                    placeholder="请填写课程的总课时数" />
            </el-form-item>
            <el-form-item label="课程简介">
                <tinymce :height="300" v-model="courseInfo.description" />
            </el-form-item>
            <el-form-item label="课程封面">
                <el-upload :show-file-list="false" :on-success="handleAvatarSuccess" :before-upload="beforeAvatarUpload"
                    :action="BASE_API + '/eduoss/upload'" class="avatar-uploader">
                    <img :src="courseInfo.cover" style="max-width: 320px;max-height: 240px">
                </el-upload>
            </el-form-item>
            <el-form-item label="课程价格">
                <el-input-number :min="0" v-model="courseInfo.price" controls-position="right"
                    placeholder="免费课程请设置为0元" /> 元
            </el-form-item>
            <el-form-item>
                <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
            </el-form-item>
        </el-form>
    </div>
</template>

<script>
import course from '@/api/course';
import subject from '@/api/subject';
import Tinymce from '@/components/Tinymce'

export default {
    components: { Tinymce },
    data() {
        return {
            saveBtnDisabled: false, // 保存按钮是否禁用
            courseInfo: {
                title: '',
                subjectId: '',
                teacherId: '',
                subjectParentId: '',
                lessonNum: 0,
                description: '',
                cover: 'https://p0.ssl.qhimgs1.com/t0158408ea977cdc80e.png',
                price: 0
            },
            BASE_API: process.env.BASE_API,
            teacherList: [],
            subjectList: [],//一级分类列表
            subSubjectList: []//二级分类列表
        }
    },
    watch: {
        $route(to, from) {
            this.init()
        }
    },
    created() {
        this.init();
    },
    methods: {
        init() {
            if (this.$route.params && this.$route.params.id) {
                const id = this.$route.params.id
                // 根据id获取课程基本信息
                this.fetchCourseInfoById(id)
            } else {
                // 初始化分类列表
                this.initSubjectList()
                // 获取讲师列表
                this.initTeacherList()
            }
        },
        fetchCourseInfoById(id) {
            course.getCourseInfoById(id).then(responseCourse => {
                this.courseInfo = responseCourse.data.item
                // 初始化分类列表
                subject.getNestedTreeList().then(responseSubject => {
                    this.subjectList = responseSubject.data.items
                    for (let i = 0; i < this.subjectList.length; i++) {
                        if (this.subjectList[i].id === this.courseInfo.subjectParentId) {
                            this.subSubjectList = this.subjectList[i].children
                        }
                    }
                })
                // 获取讲师列表
                this.initTeacherList()
            }).catch((response) => {
                this.$message({
                    type: 'error',
                    message: response.message
                })
            })
        },
        handleAvatarSuccess(res) {
            this.courseInfo.cover = res.data.url
        },
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2
            if (!isJPG) {
                this.$message.error('上传头像图片只能是JPG格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过2MB!')
            }
            return isJPG && isLt2M
        },
        subjectLevelOneChanged(value) {
            for (let i = 0; i < this.subjectList.length; i++) {
                if (this.subjectList[i].id === value) {
                    this.subSubjectList = this.subjectList[i].children
                    //清空二级下拉列表内容
                    this.courseInfo.subjectId = ''
                }
            }
        },
        initSubjectList() {
            subject.getNestedTreeList().then(response => {
                this.subjectList = response.data.items
            })
        },
        initTeacherList() {
            course.getTeacherList().then(response => {
                this.teacherList = response.data.teachers
            })
        },
        updateCourse() {
            this.saveBtnDisabled = true
            course.updateCourseInfoById(this.courseInfo).then(response => {
                this.$message({
                    type: 'success',
                    message: '修改成功!'
                })
                return response// 将响应结果传递给then
            }).then(response => {
                this.$router.push({ path: '/course/chapter/' + this.courseInfo.id })
            }).catch((response) => {
                // console.log(response)
                this.$message({
                    type: 'error',
                    message: '保存失败'
                })
            })
        },
        addCourse() {
            course.saveCourseInfo(this.courseInfo).then(response => {
                this.$message({
                    type: 'success',
                    message: '保存成功!'
                });
                return response; // 将响应结果传递给then
            }).then(response => {
                this.$router.push({ path: '/course/chapter/' + response.data.courseId });
            }).catch((response) => {
                this.$message({
                    type: 'error',
                    message: response.message
                })
            });
        },
        saveOrUpdate() {
            if(!this.courseInfo.id){
                this.addCourse();
            }else{
                this.updateCourse();
            }
        }
    }
}
</script>

<style scoped>
.tinymce-container {
    line-height: 29px;
}
</style>